Question:
Find the average of odd numbers from 9 to 1061
Correct Answer
535
Solution And Explanation
Solution
Method (1) to find the average of the odd numbers from 9 to 1061
Shortcut Trick to find the average of the given continuous odd numbers
The odd numbers from 9 to 1061 are
9, 11, 13, . . . . 1061
After observing the above list of the odd numbers from 9 to 1061 we find that the difference between two consecutive terms are equal. This means the list of the odd numbers from 9 to 1061 form an Arithmetic Series.
In the Arithmetic Series of the odd numbers from 9 to 1061
The First Term (a) = 9
The Common Difference (d) = 2
And the last term (ℓ) = 1061
The average of the numbers forming an Arithmetic Series
= The first term (a) + The last term (ℓ)/2
⇒ The average of numbers forming an Arithmetic Series = a + ℓ/2
Thus, the average of the odd numbers from 9 to 1061
= 9 + 1061/2
= 1070/2 = 535
Thus, the average of the odd numbers from 9 to 1061 = 535 Answer
Method (2) to find the average of the odd numbers from 9 to 1061
Finding the average of given continuous odd numbers after finding their sum
The odd numbers from 9 to 1061 are
9, 11, 13, . . . . 1061
The odd numbers from 9 to 1061 form an Arithmetic Series in which
The First Term (a) = 9
The Common Difference (d) = 2
And the last term (ℓ) = 1061
The Average of the given numbers
= Sum of the given numbers/Total number of given numbers
Thus, to find the average of the given numbers, first, we need to find their sum and the total number of given numbers
Finding the number of terms
For an Arithmetic Series, the nth term
an = a + (n – 1) d
Where
a = First term
d = Common difference
n = number of terms
an = nth term
Thus, for the given series of the odd numbers from 9 to 1061
1061 = 9 + (n – 1) × 2
⇒ 1061 = 9 + 2 n – 2
⇒ 1061 = 9 – 2 + 2 n
⇒ 1061 = 7 + 2 n
After transposing 7 to LHS
⇒ 1061 – 7 = 2 n
⇒ 1054 = 2 n
After rearranging the above expression
⇒ 2 n = 1054
After transposing 2 to RHS
⇒ n = 1054/2
⇒ n = 527
Thus, the number of terms of odd numbers from 9 to 1061 = 527
This means 1061 is the 527th term.
Finding the sum of the given odd numbers from 9 to 1061
The sum of all terms (S) in an Arithmetic Series
= n/2 (a + ℓ)
Where, n = number of terms
a = First term
And, ℓ = Last term
Thus, the sum of all terms (S) of the given odd numbers from 9 to 1061
= 527/2 (9 + 1061)
= 527/2 × 1070
= 527 × 1070/2
= 563890/2 = 281945
Thus, the sum of all terms of the given odd numbers from 9 to 1061 = 281945
And, the total number of terms = 527
Since, the average of the given numbers
= Sum of the given numbers/Total number of given numbers
Thus, the average of the given odd numbers from 9 to 1061
= 281945/527 = 535
Thus, the average of the given odd numbers from 9 to 1061 = 535 Answer
Similar Questions
(1) Find the average of odd numbers from 7 to 729
(2) Find the average of the first 4331 even numbers.
(3) Find the average of even numbers from 4 to 1524
(4) Find the average of odd numbers from 9 to 889
(5) Find the average of even numbers from 6 to 1368
(6) Find the average of the first 3806 even numbers.
(7) What will be the average of the first 4578 odd numbers?
(8) Find the average of the first 4077 even numbers.
(9) What will be the average of the first 4220 odd numbers?
(10) Find the average of the first 1994 odd numbers.